Animal feeding and monitoring system

ABSTRACT

The animal feeding and monitoring system includes an electronic identity tag having a code generator for generating a coded identifier signal uniquely associated with an animal to be identified. Electromagnetic energy from an RF field generator mounted in a feeding station is coupled into a pick-up coil in the electronic identity tag when the animal wearing the electronic identity tag approaches the feeding station. Electromagnetic energy coupled into the pick-up coil serves a source of power for the operating components of the tag. The code generator generates the coded identifier signal in response to timing pulses supplied by either an independently set RC oscillator circuit or a countdown circuit connected to the pick-up coil. A voltage detector connected to the pick-up coil is connected to gate the coded identifier signal transmissions only when sufficient power to provide error-free operation of the code generator has accumulated in the pick-up coil. 
     Once the animal has been identified, certain control and monitoring functions can be performed under the command of a central computer. The central computer can direct the delivery of feed to the identified animal in accordance with that animal&#39;s feeding requirements. Where the animal to be identified is a cow, feed consumption, milk production and temperature measurements for a particular cow can be obtained and stored over a period of time, enabling the central computer to determine the feeding requirements for that cow. Additional monitoring and diagnostic routines can be performed by the central computer to ascertain whether the cow is in heat or has mastitis. A multiplexing arrangement permits these various control, monitoring and diagnostic routines to be performed for a plurality of animals located in adjacent feeding stations.

TECHNICAL FIELD

The present invention relates to a system for feeding and monitoringindividual animals in a herd of animals, and more specifically relatesto a system which electronically identifies individual animals by meansof a coded identifier signal transmitted from an electronic identity tagworn by the animal and which thereafter dispenses measured quantities offeed to the identified animal while performing related animal monitoringand diagnosing functions.

BACKGROUND ART

Systems heretofore developed for electronically identifying separateanimate or inaminate objects in a group of objects, particularly thosesystems designed to distinguish between animals in a herd for thepurpose of controlling the feed dispensed to the animals, can generallybe divided into one of two classes. Systems in the first class carry outthe identification process on a gross level only, taging certain objectswith an electronic distinguishing marker and then simply sorting all ofthe objects according to whether they have or have not been tagged. Forexample, where certain animals in a herd are selected to receive feedsupplements, an electronic distinguishing marker which activates aswitching circuit connected to control delivery of the feed supplementto a feeding station is attached to the selected animal. Such electronicdistinguishing markers may take many forms, including devices whichdisturb the magnetic field surrounding a magnetic switching circuit, asdisclosed in U.S. Pat. No. 4,162,683 issued to Brooks and U.S. Pat. No.4,188,912 issued to Smalley; and devices which damp, absorb or otherwisedisturb the RF field generated by a RF switching circuit, as disclosedin U.S. Pat. No. 3,465,724 issued to Broadbent, U.S. Pat. No. 3,541,995issued to Fathauer and U.S. Pat. No. 3,557,757 issued to Brooks.

Systems in the second class provide a means for identifying animate orinanimate objects in a true sense. That is, each animate or inanimateobject in a group of objects is tagged with an electronic marker havinga characteristic uniquely associated with that object. The electronicmarker or identity tag is subsequently "read" via suitable electroniccircuitry to obtain the object identity, and the object identity soobtained is used to initiate various control or monitoring sequences.One important application for systems of the second class involves theidentification of animals and the dispensing of feed on the basis of theidentified animals' individual feed requirements.

Some prior art animal feeding systems employ identity tags havingpassive RF circuits similar to the RF circuits of the aforementionedBroadbent and Brooks patent, wherein RF energy is absorbed by a detectorat several predetermined frequencies uniquely arranged to provide ameans for identifying the animals. U.S. Pat. No. 3,516,575 issued toMoffitt and U.S. Pat. No. 3,557,758 issued to Lack disclose passive RFenergy absorbing type identity tags. Other prior art animal feedingsystems employ identity tags having active RF circuits which radiate RFenergy at discrete frequencies to provide a means for identifying theanimals. These discrete frequencies are received by a plurality ofreceiving circuits mounted at or near the animal feeding station. Thelatter type of active RF identity tag system is disclosed in U.S. Pat.No. 3,180,321 issued to Aldinger.

Frequency-dependent animal identification processes such as thoseillustrated in the Broadbent, Moffitt and Lack patents are entirelyadequate for many applications. Where digital control means are utilizedto control the feed delivery operation, however, frequency-dependentsystems must be properly interfaced with the digital controller beforethe identification process can be completed. This interface generallyrequires an extra analog to digital conversion step in thefrequency-dependent signal receiving apparatus, with an attendantincrease in circuit complexity and cost. It would be of obviousadvantage if the identifier signal radiated from the identity tag werealready in digital form.

Perhaps the simplest manner of digital identification involves a simplecount. An animal is assigned an identification number, an identity taghaving a counter programmed to supply the predetermined number or countis attached to the animal, and whenever a receiver in the vicinity ofthe animal detects the predetermined count, the animal is identified.U.S. Pat. No. 3,929,277 issued to Byrne both disclose counting-typeidentity tags. In the Byrne et al system, a series of RF pulsescorresponding in number to a predetermined count are generated by anidentity tag counter and transmitted to a receiver for counting. In theRodrian system, the identity tag counter counts to a predetermined valueand then merely transmits a reset pulse to stop the count in asynchronized counter connected to the system transceiver.

Although animal identification signals developed by counting-typeidentity tags are more conveniently interfaced with digital controlmeans than those developed by frequency-dependent identity tags, if thenumber of animals to be identified is quite large, it becomes somewhatcumbersome to actually count RF identification pulses. It would thus beeven more advantageous to generate an animal identifier signal incompact, coded form for transmission to a digital receiver/decoder.Standard integrated circuit technology could be employed to constructsuitable code generators and receive/decoders at low cost and withreduced size. Further economies of cost and size could be realized byeliminating the need for a separate identity tag power supply in favorof a simple energy absorbing circuit in the identity tag, into which RFenergy could be coupled to provide a ready source of power. The ease andconvenience of transmitting binary coded identifier signals from anelectronic identity tag would render the tag fully compatible with mostdigital computer configurations, in turn increasing the range ofcontrol, monitoring and diagnostic functions available to an animalfeeding and monitoring system.

DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention to provide a systemfor feeding and monitoring animals.

It is another object of the present invention to provide an animalfeeding and monitoring system wherein the animal to be identified wearsan electronic identity tag capable of generating and transmitting acoded identifier signal.

It is still another object of the present invention to provide anelectronic identity tag having a code generator for generating codedidentifier signals uniquely associated with the animal wearing the tag,which code generator is powered by electromagnetic energy coupled intothe electronic identity tag from a remote electromagnetic energy source,thereby obviating the need for an internal tag power supply.

It is a further object of the present invention to provide an electronicidentity tag having a pick-up coil for receiving electromagnetic energyfrom a remote source and a code generator powered by the electromagneticenergy so received to generate a coded identifier signal at a frequencyindependent of the frequency of the received electromagnetic energy.

It is yet another object of the present invention to provide anelectronic identity tag having a pick-up coil for receivingelectromagnetic energy from a remote source and a code generator poweredby the electromagnetic energy so received to generate a coded identifiersignal at a frequency proportional to the frequency of the receivedelectromagnetic energy.

It is an additional object of the present invention to provide an animalfeeding and monitoring system employing an RF field generator forcoupling RF operating power into an electronic identity tag worn by ananimal to be identified.

It is an additional object of the present invention to provide an animalfeeding and monitoring system wherein the RF field generator employed tocouple operating power into an electronic identity tag worn by an animalto be identified is capable of selectively increasing the coupling rangeof the RF field so generated in order to compensate for variations indistance between the RF field generator and the electronic identity tag.

It is also an object of the present invention to provide an animalfeeding and monitoring system capable of identifying and feeding aplurality of animals in adjacent feeding stations.

It is another object of the present invention to provide a method formonitoring the milk production of an identified cow in order toconstruct a lactation curve for the identified cow, thereby establishinga basis for determining the feed requirements of the identified cow.

It is a further object of the present invention to provide a method formonitoring the temperature, feed consumption and milk production of anidentified cow in order to ascertain whether the identified cow is inheat.

It is a still further object of the present invention to provide amethod for monitoring the temperature, feed consumption and milkproduction of an identified cow in order to diagnose the occurrence ofmastitis in the identified cow.

An additional object of the present invention is to provide a system andmethod for monitoring pounds of milk production and percent of butterfatin the milk produced by an identifiable cow as well as udder temperatureand the udder somatic cell count.

These and other objects of the present invention are accomplished withan animal feeding and monitoring system in which an animal to beidentified wears an electronic identity tag having a code generator forgenerating a coded identifier signal uniquely associated with the animalto be identified. Electromagnetic energy from an RF field generatormounted in a feeding station is coupled into a pick-up coil in theelectronic identity tag when the animal wearing the electronic identitytag approaches the feeding station. Electromagnetic energy coupled intothe pick-up coil serves as a source of power for the operatingcomponents of the tag. The code generator generates the coded identifiersignal in response to timing pulses supplied by either an independentlyset RC oscillator circuit or a countdown circuit connected to thepick-up coil. Where the RC oscillator circuit is used, the frequency ofthe coded identifier signal generated by the code generator isindependent of the frequency of electromagnetic energy coupled into thepick-up coil. Where the countdown circuit is used, the coded identifiersignal frequency is proportional to the frequency of the received orcoupled electromagnetic energy. A voltage detector connected to thepick-up coil is connected to gate the coded identifier signaltransmissions only when sufficient power to provide error-free operationof the code generator has accumulated in the pick-up coil.

Because the coded identifier signals transmitted from the electronicidentity tag can vary somewhat in frequency, particularly if the RCoscillator is used to supply timing pulses to the code generator, theanimal feeding and monitoring system of the present inventionincorporates a receiver with a frequency lock feature. Othermodifications to the system include the provision of an RF fieldgenerator which can be stepped through progressively more powerful fieldgenerating modes. Thus, the coupling range of the RF field generator canbe incrementally increased to precisely compensate for variations indistance between the electronic identity tag and the RF field generator,which variations result from unpredictable movement of the animalwearing the electronic identity tag.

Once the animal has been identified, certain control and monitoringfunctions can be performed under the command of a central computer. Forinstance, the central computer can direct the delivery of feed to theidentified animal in accordance with that animal's feeding requirements.Where the animal to be identified is a cow, feed consumption, milkproduction and temperature measurements for a particular cow can beobtained and stored over a period of time, enabling the central computerto determine the feeding requirements for that cow. Additionalmonitoring and diagnostic routines can be performed by the centralcomputer to ascertain whether the cow is in heat or has mastitis. In oneembodiment of the present invention, a multiplexing arrangement permitsthese various control, monitoring and diagnostic routines to beperformed for a plurality of animals located in adjacent feedingstations.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects and advantages of the present invention willbecome more apparent from the following Brief Description of theDrawings and Best Mode for Carrying Out the Invention, wherein

FIG. 1 is a schematic representation of the animal feeding andmonitoring system of the present invention;

FIG. 2 is a block diagram of an electronic identity tag for use in thesystem of the present invention, the electronic identity tag having acode generator supplied with timing pulses by an RC oscillator circuit;

FIG. 3 is a block diagram of a receiver circuit particularly suited foruse with the electronic identity tag of FIG. 2;

FIG. 4 illustrates a modified electronic identity tag having a countdowncircuit for supplying timing pulses to the code generator;

FIG. 5 illustrates a RF field generator capable of generatingprogressively more powerful RF fields under the control of the systemcentral computer;

FIGS. 6A-6D schematically represent the operation of the FIG. 5 RF fieldgenerator;

FIG. 7 illustrates a muliplexing arrangement for use when a plurality ofanimals in adjacent feeding stations are to be identified;

FIG. 8 graphically depicts a lactation curve for a hypothetical cow; and

FIG. 9 graphically depicts the changes in temperature, feed consumptionand milk production which indicate that a particular cow is in heat.

BEST MODE FOR CARRYING OUT THE INVENTION

The animal feeding and monitoring system of the present invention isshown schematically in FIG. 1. The system provides a means foridentifying individual animals in a group or herd or animals, whereuponvarious data collected in connection with an identified animal can betagged and stored for subsequent processing. System operation isinitiated by an electronic identity tag 2, carried on the animal to beidentified and monitored. For the sake of convenience, a cow 4 isillustrated in FIG. 1, but it is to be understood that the system can beemployed with other types of animals, both domestic and wild. Electronicidentity tag 2 is secured to the cow by a suitable means such as a chain6. When the cow approaches feeding station 8, RF energy from an RF fieldgenerator 10 is electromagnetically coupled into the electronic identitytag. RF generator 10 includes an RF supply 12 and an RF coil 14 forestablishing an RF field in the vicinity of feeding station 8.Electronic identity tag 2 thereafter functions as described in detailhereinbelow to transmit the coded identifier signal uniquely associatedwith cow 4. This coded identifier signal is picked up by a receivingantenna 16 and processed in a receiver 18 which communicates the cow' sidentity to a central computer 20 via data link 22. Central computer 20can perform a number of control and measuring routines. For example,upon receipt of the cow's identity, central computer 20 can instruct amotor controller 24 via data link 26 to activate motor 28 for a preciseinterval computed in accordance with the feeding requirements of theidentified cow. Motor 28 in turn drives feed delivery mechanism 30 todeliver a carefully measured quantity of feed 32 from feed hopper 34 tothe feed trough 36 of feeding station 8. A faulty feed deliveryindicator 38 may be connected to central computer 20 to signal theoccurrence of a fault condition in either motor 28 or feed deliverymechanism 30. The faulty feed delivery indicator includes a currentsensing coil 40 mounted to detect the level of current passing frommotor controller 24 through current input lines 42 to motor 28. Theoutput from current sensing coil 40 is amplified by current amplifier 44and supplied to remote computer 20 on lead 46. When the value of thecurrent level detected by current sensing coil 40 is compared againstthe normal load current value stored in computer 20, a determination ofthe feed delivery situation can be made. If the detected current levelexceeds the normal current level by a predetermined amount, motoroverload is indicated, while detected current levels more than apredetermined amount below the normal current levels indicate that motor28 is underloaded due to emptying of hopper 34. In either case, centralcontroller 20 can activate an alarm (not shown) to alert the feedingstation operator to the detected condition.

Where feeding station 8 or a separate milking station, includes amilking apparatus 48, a measure of the yield or quantity of milkobtained from the identified cow during milking, as well as thetemperature and somatic cell count of the milk so obtained, can beascertained by appropriate sensors 50,52 and supplied along leads 54,56to central computer 20 for use in one of several diagnostic proceduresdescribed in greater detail hereinbelow. Milk quantity may be indicatedby a liquid level sensor, weight sensor or other known sensors adaptedto indicate the quantity of fluid in a container.

Finally, a data link 58 between central computer 20 and RF fieldgenerator 10 enables the central computer to govern the energy inputlevel to the RF field generator. Hence, the strength of the RF fieldgenerator output may be adjusted to carry out the electronic identitytag locating procedure further disclosed in connection with FIGS. 5 and6.

FIG. 2 is a block diagram of one embodiment of an electronic identitytag 2 constructed in accordance with the present invention. Theelectronic identity tag of FIG. 2 includes a pick-up coil 60, arectifier 62, and RC oscillator circuit 64, a code generator 66, avoltage detector 68, an AND gate 70, a transmitter chip 72 and atransmitting antenna 74. The pick-up coil 60 functions in a manneranalogous to a transformer secondary to receive RF energy from the RFcoil 14 of RF generator 10. The RF energy received or coupled intopick-up coil 60 is recitified in recitifier 62 and conducted along lead76 to a power tap 78. Power tap 78 serves as a source of power for theremainder of the electronic identity tag.

RC oscillator circuit 64 draws power from power tap 78 to produce aseries of timing pulses having a period dependent on the time constantof the RC or crystal oscillator circuit. Each timing pulse is inputalong lead 80 to code generator 66, which thereafter generates theaforementioned coded identifier signal uniquely associated with cow 4.Code generator 66 may comprise a programmable encoder of the typemanufactured by Supertex, Inc. of Sunnyvale, Calif., under thedesignation ED-9 or ED-15. The ED-9 encoder has a capacity of fivehundred and twelve different binary coded addresses and thus anelectronic identity tag employing the ED-9 encoder can be programmed tooutput any one of five hundred and twelve coded identifier signals.

The coded identifier signals from code generator 66 are fed along lead82 to AND gate 70. The purpose of AND gate 70 is to reduce the errorrate in transmissions of the coded identifier signals from theelectronic identity tag 2 to the receiving antenna 16 of feeding station8. As cow 4 initially approaches the feeding station, pick-up coil 60begins to receive RF energy from the RF generator 10. This RF energy,however, is generally of a level insufficient to power the RC oscillatorcircuit 64 and the code generator 66 until the cow moves to within acertain distance of the RF coil 14. Insufficient RC oscillator circuitand code generator power, of course, produces errors in the codedidentifier signal output from the code generator. To prevent sucherroneous coded identifier signals and the consequent misidentificationof the cow wearing the electronic identity tag, the remaining lead 84 ofAND gate 70 is connected to voltage detector 68. The input lead 86 tovoltage detector 68 is in turn connected to the power tap 78. A gateenabling signal is supplied to the AND gate 70 from voltage detector 68along lead 84 only when the voltage at the power tap 78 exceeds apredetermined threshold voltage of the voltage detector, whichpredetermined threshold voltage is set to a level above that necessaryto supply minimum operating power to the RC oscillator circuit 64 andthe code generator 66. With the AND gate enabled, the coded identifiersignals can then pass along lead 86 to transmitter chip 72 andtransmitting antenna 74 for error-free transmission of receiving antenna16 in the feeding station 8.

The transmission frequency of the coded identifier signals from theelectronic identity tag 2 of FIG. 2 is a function of the frequency ofthe timing pulses supplied to code generator 66 by RC oscillator circuit64. The frequency of the timing pulses, as previously mentioned, dependsupon the RC time constant of the RC oscillator circuit. Due to minormanufacturing variations, changes in ambient temperature, or the like,this time constant may vary somewhat between the individual electronicidentity tags uniquely associated with each cow. In order to insureproper detection of the coded identifier signals regardless of variationin transmitting frequency, the receiving antenna 16 and receiver circuit18 of FIG. 1 must be capable of scanning a relatively wide frequencyband and locking onto the particular discrete frequency at which anygiven set of coded identifier signals are being transmitted. Such areceiving antenna and receiver circuit arrangement is illustrated inFIG. 3. Receiver circuit 18 of FIG. 3 includes a receiver chip 88 whichis supplied with a reference frequency by a variable frequency source90. Variable frequency source 90 may comprise a voltage controlledoscillator or similar type of device having a frequency output whichvaries in response to changing inputs. A counter circuit 92 is connectedto input an ordered sequence of control pulses to the variable frequencysource 90, thereby stepping the reference frequency from the variablefrequency source at predetermined intervals through the range ofavailable frequencies. When the coded identifier signals arrive atreceiving antenna 16, they are amplified in an amplifier 94 and fed toreceiver chip 88. Counter circuit 92 is activated to begin the frequencystepping or scanning process, and when the reference frequency suppliedby variable frequency source 90 matches the transmission frequency ofthe coded identifier signal, a detector 96 senses the match and locksthe counter unit 92 onto the particular control pulse producing thematching reference frequency. Subsequently, the coded identifier signalscan be detected in receiver chip 88 and directed to central computer 20over data link 22.

If desired, the electronic identity tag 2 of FIG. 2 can be modified asindicated in FIG. 4 to eliminate the need for a scanning receivercircuit of the type illustrated in FIG. 3. The overall functioning ofthe FIG. 4 electronic identity tag is similar in most respects to thatof FIG. 2 tag, with tag components in FIG. 4 having the same referencenumerals as like components in FIG. 2. Thus, pick-up coil 60 receivesenergy from RF field generator 10, and recitifier 62 recitifies thereceived RF energy to provide power tap 78 with tap operating power.Code generator 66 generates a coded identifier signal which uniquelyidentifies the cow carrying or wearing the electronic identity tag 2. Inthe interest of completeness, the internal elements of the Supertex,Inc. ED-9 programmable encoder employed as the code generator in FIG. 2have been schematically blocked out in FIG. 4. Appropriate cuts in thedata bit inputs 98 to the ED-9 encoder are used to set the desiredbinary Manchester-encoded address forming the coded identifier signalfor a particular cow. Voltage detector 68 and AND gate 70 operate in themanner previously disclosed to insure that no transmission of the codedidentifier signal from transmitter chip 72 and transmitting antenna 74occur until the power supplied at power tap 78 is sufficient to enableerror-free operation of the code generator 66. In contrast to the FIG. 2embodiment, however, code generator 66 in the FIG. 4 embodiment isdriven by a countdown circuit 100 which produces a timing pulseproportional to the frequency of the RF energy generated by RF fieldgenerator 10. Countdown circuit 100 is connected to detect the frequencyof the incoming RF energy in pick-up coil 60 via lead 102. Internallogic frequency divider circuitry of a conventional type in thecountdown circuit divides the RF field frequency by a predeterminedamount to provide a series of timing pulses of proportional frequency onlead 104. The timing pulses are input to code generator 66, and thecoded identifier signals are subsequently generated and transmitted at asingle discrete frequency dependent on the frequency of the timingpulses. Armed with knowledge of the internal logic of the countdowncircuit 100, the system operator can accurately calculate this singlediscrete transmission frequency of the coded identifier signals. Thus, aconventional receiver circuit tuned to the transmission frequency ascalculated can be employed at feeding station 8 in lieu of the FIG. 3receiver circuit to receive and detect the coded identifier signals.

A problem in the use of electronic identity tag 2 with a particular cowmay be encountered where the cow enters feeding or milking station 8 butdoes not move close enough to the RF field generator 10 to couple energyinto the pick-up coil of the electronic identity tag at a levelsufficient to exceed the threshold level of voltage detector 68 andenable AND gate 72 for transmission of the coded identifier signals. Asmay be surmised, this problem arises because the cow is not restrictedto a single, well defined position in the feeding or milking station. Onthe contrary, the cow can occupy any one of several locations within thefeeding station, each such location placing the electronic identity tag2 worn by the cow at a different distance from RF field generator 10. RFsupply 12 can nonetheless be constructed as shown in FIG. 5 to overcomethe disadvantages associated with the unpredictable movement of the cowand the associated electronic identity tag. A frequency generator 106connected to RF coil 14 serves as the basic source of RF energy for theRF field generator. Although the RF output from frequency generator 106exhibits a characteristic fixed frequency established by the electricalvalues of the frequency generator components, the amplitude of thefrequency generator RF output, and hence, the power content of the RFenergy radiating from RF coil 14, can be varied depending upon the levelof voltage input to the frequency generator. Accordingly, a transformer108 having a series of voltage taps t₁, t₂ . . . t_(x) for respectivelysupplying progressively increasing voltage levels is connected to thefreuqency generator. A series of AND gates 110 connected between thevoltage taps t₁ -t_(x) and the frequency generator selectively apply thetransformer voltage levels to the frequency generator in response to aset of enabling signals from counter 112. The set of enabling signalsare generated in an ordered sequence such that AND gate 110 connected tovoltage tap t₁ is first enabled, followed by AND gate 110 connected tovoltage tap t₂, AND gate 110 connected to voltage tap t₃ and so on untilthe AND gate 110 connected to voltage tap t_(x) is finally enabled. Noneof the enabling signals from counter 112 overlap, and thus only one ANDgate at a time may be closed. It can now be seen that the successiveaction of the AND gates, in combination with the progressivelyincreasing voltages on taps t₁ -t_(x), input progressively increasingvoltages to frequency generator 106. As a result, the frequencygenerator outputs RF energy in progressively increasing output levels,and the coupling range of RF coil 14 is progressively expanded withrespect to electronic identity tag 2.

FIGS. 6A through 6D illustrate the operation of field generator 10 ingraphic form. Using an exemplary four tap transformer 108 with 20 volt,40 volt, 80 volt and 160 volt potentials supplied on voltage taps t₁,t₂, t₃ and t_(x), the enabling of AND gate 110 connected to voltage tapt₁ produces the relative frequency generator RF output indicated in FIG.6A. The enabling of AND gate 110 connected to voltage tap t₂ producesthe relative frequency generator RF output indicated in FIG. 6B. FIG. 6Cdepicts the relative frequency generator RF output produced when ANDgate 110 connected to voltage tap t₃ is enabled, while FIG. 6D depictsthe relative frequency generator RF output produced when AND gate 110connected to voltage tap t₄ is enabled. With an RF field generator suchas that disclosed in FIG. 5 compensation for variation in distancebetween a cow with its associated electronic identity tag 2 and RF coil14 is a simple matter. At the beginning of the cow identificationprocess, computer 20 instructs counter 112 via data link 58 to initiatethe enabling signal sequence. The input voltage level to frequencygenerator 106 is subsequently increased to step the frequency generatorRF output through ever greater amplitudes until a coded identifiersignal is at last received from electronic identity tag 2. At this pointthe enabling sequence is interrupted to lock the currently-enabled ANDgate 110 into closed condition for a period of time sufficient to permitverification of the coded identifier signal in central computer 20. Atthe completion of coded identifier signal verification, central computer20 can shut counter 112 down until the next cow to be identified hasentered the feeding station 8. If no coded identifier signal is receivedat receiving antenna 16 after the highest available voltage fromtransformer 108 has been applied to frequency generator 106, of course,central computer 20 recognizes a "no cow present" status for the feedingstation.

It is common practice on a dairy farm to employ a number of adjacentstalls or "milking parlors" wherein a plurality of cows can be fedand/or milked simultaneously. The animal feeding and measuring system ofthe present invention can be adapted to such an arrangement. Each stallis equipped with a feeding station 8, and the motor controller data link26, faulty feed delivery indicator lead 46, milk yield sensor lead 54and milk temperature, percent butterfat and somatic cell sensor lead 56from each feeding station are connected directly to central computer 20.In order to prevent the RF fields produced by RF field generators inadjacent stalls from interfering with one another, however, it isnecessary to time multiplex the operation of the RF field generators 10and receiver circuits 18 at the individual feeding stations. To thisend, a multiplexer 114, shown in FIG. 7, is connected across data links22 and 58 respectively providing communication between the centralcomputer 20, the receiver circuit and the RF field generator.Multiplexer 114 functions to insure that control signals directed fromcentral computer 20 to the counters 112 in the RF field generators ofadjacent feeding stations reach only one counter at a time, thereby"activating" only one feeding station at a time. Likewise, only thosecoded identifier signals detected in the receiving circuit 18 associatedwith the "activated" feeding station can pass through multiplexer 114 tocentral computer 20. Upon further reflection, it is evident that theaction of multiplexer 114 in sequencing the operation of the RF fieldgenerators 10, together with the action of the FIG. 5 RF supply 10 inproviding controlled expansion of the RF field generator coupling range,tends to minimize the possibility that the receiving circuit 18 in a"activated" feeding station will mistakenly detect the coded identifiersignal from the electronic identity tag worn by a cow in an adjacentfeeding station.

Once a particular cow has been identified by detecting and verifying theunique coded identifier signal associated with that cow, centralcomputer 20 can perform numerous control and diagnostic determinationspertinent to the identified cow. For example, the aforementioneddelivery of a carefully measured quantity of feed, based on the feedingrequirements of the identified cow, can be automatically carried out inthe central computer by ascertaining the identified cow's position inher lactation cycle. FIG. 8 illustrates a typical lactation curve 116for a hypothetical cow. During periods of increasing milk production,indicated by region A in FIG. 8, a cow generally requires a high feed tomilk production ratio R_(i), say one pound of feed for each pound ofmilk produced. During peak periods of milk yield or production in thelactation cycle, indicated by region B in FIG. 8, the cow's feedrequirements level off somewhat, giving a feed to milk ratio R_(p) of,say, one pound of feed for each two pounds of milk produced. During thedecreasing period of milk production in the cow's lactation cycleindicated by region C in FIG. 8, the cow's feed requirements taper offsignificantly, giving a feed to milk ratio R_(d) of, say, one pound offeed for each four pounds of milk produced. An identified cow's positionin her lactation cycle can be approximated by means of some simplecalculations. Where current milk production P_(c) exceeds the previousday's milk production P_(p) by a predetermined amount, i.e.,:

    P.sub.c -P.sub.p >A,

the cow is in a increasing period of milk production. Where current milkproduction differs from the previous day's milk production by less thana predetermined amount, i.e.:

    P.sub.c -P.sub.p <B,

the cow is in her peak period of milk production. Finally, where currentmilk production is less than the previous day's milk production by apredetermined amount, i.e.:

    P.sub.c -P.sub.p <-C,

the cow is in her decreasing period of milk production. Having thuscomputed the cow's position on the lactation curve, the cow's feedrequirements can be determined by a second series of simplecomputations. Where the cow is in her increasing milk production period,the feed ratio for the increasing production period R_(i) is multipliedby current milk production P_(c) to obtain the quantity of feed whichmust be metered out by central computer 20:

    Amount of Feed=R.sub.i ×P.sub.c

Where the cow is in her peak period of milk production, the feed ratiofor the peak period R_(p) is multiplied by current milk production P_(c)to obtain the necessary quantity of feed:

    Amount of Feed=R.sub.p ×P.sub.c

Where the cow is in her decreasing period of milk production, the amountof feed required is obtained by multiplying the ratio for the decreasingperiod R_(d) by the current milk production:

    Amount of Feed=R.sub.d ×P.sub.c

After completion of the relevant calculations, of course, centralcomputer 20 directs motor controller 24 to activate motor 26 and deliverthe proper amount of feed, as previously disclosed.

Central computer 20 can also be programmed to alert the system operatorto the fact that an identified cow is in heat. The ability to detectwhen a cow is in heat is important, inasmuch as the cow should be bredas soon as possible after it enters heat. Generally speaking, thetemperature of a cow in heat rises somewhat while the cow's feedconsumption and milk production drop off. This relationship isgraphically illustrated in FIG. 9. If the temperature, feed consumptionand milk production variables for a cow identified in accordance withthe present invention are monitored over a period of time, then, centralcomputer 20 can accurately track the relationship between these threevariables and provide some sort of output signal when the variablerelationship indicates that the identified cow is in heat. The cow'stemperature is reflected in the temperature of the milk produced by thecow and thus can be measured by sensor 52 in feeding station 8.Similarly, the cow's milk yield or production is measured as disclosedabove by sensor 50 in the feeding station. In order to determine feedconsumption, a weighing device (not shown) or the like can be mountedunder the feeding station trough to gauge the amount of feed actuallyconsumed by the cow following delivery of the feed from feed hopper 34.The changes in temperature, feed consumption and milk production fromday to day, respectively designated T F and M are determined andcompared against the average temperature, feed consumption and milkproduction, respectively designated T_(avg), F_(avg) and M_(avg), bymeans of a function having the general form:

    T=K.sub.1 (Δt/T.sub.avg)+K.sub.2 (Δf/F.sub.avg)+K.sub.3 (Δm/M.sub.avg)

where K₁, K₂ and K₃ are constants. The value for a given T, F, and M inexcess of a predetermined value indicate that the cow identified inconnection with the given T, F, M is in heat. If desired, adjustments tothe predetermined value can be made to increase or decrease thesensitivity of the heat detection process.

Another program can be designed to enable central computer 20 todiagnose mastitis, i.e., an infectious disease of the udder, inidentified cows. As was the case with a cow in heat, a cow havingmastitis exhibits decreased feed consumption and reduced milkproduction. The temperature rise characteristic of mastitis, however,occurs only in the infected quadrant of the udder. Consequently, it isnecessary to provide the milking apparatus 36 of FIG. 1 withconventional individual milking cups (not shown) and temperature sensorsfor each quadrant. Various udder temperatures, the feed consumption, andthe milk production are monitored in a fashion similar to that employedto detect a cow in heat, and appropriate calculations are performed tocompare the temperature in each utter T_(u1) -T_(u4) with the averageudder temperature T_(uavg), where:

    T.sub.uavg =(t.sub.u1 +t.sub.u2 +t.sub.u3 +t.sub.u4)/4

If any of the utter temperatures exceeds the average udder temperatureby a predetermined amount, i.e., where either:

    t.sub.ul -t.sub.uavg >K.sub.1 or

    t.sub.u2 -t.sub.uavg >K.sub.2 or

    t.sub.us -t.sub.uavg >K.sub.3 or

    t.sub.u4 -t.sub.uavg >K.sub.4,

and the current feed consumption f_(c) is less than the average feedconsumption f_(avg), i.e., where

    f.sub.avg -f.sub.c <K.sub.5 ;

and the current milk production P_(c) is less than the average milkproduction P_(avg) by a predetermined amount i.e., where:

    P.sub.avg -P.sub.c <K.sub.6 ;

mastitis is indicated. The infected quadrant of the identified cow'sudder is ascertained by noting which of the four udder temperaturest_(u1) -t_(u4) exceeds the average udder temperature t_(uavg) by thepredetermined amount. A suitable alarm can thereafter be generated toalert the system operator to the presence of mastitis in the identifiedcow.

Additionally, the somatic cell count is a direct indication of mastitis.To determine this count, the sensors 52 will include a conductivitysensor to determine the electrical conductivity of the milk. The cellcount is directly pproportional to the conductivity of the milk, andthis information may be sent along lead 56 and registered in thecomputer 20.

Finally, the sensors 52 may include photo optical sensors or other knownsensors to measure the milk density. This milk density informationprovided to the computer on the lead 56 is a direct indication of thebutterfat content of the milk.

INDUSTRIAL APPLICABILITY

The animal feeding and monitoring system of the present invention can beutilized to tag and identify individual members of a group or herd ofanimals in order to carry out certain control and monitoring functionswith regard to the identified animals. Carefully measured quantities offeed, for instance, can be delivered to an identified animal inaccordance with the particular feeding requirements of that animal. Heatcycles in identified animals can be detected, and the system operatorcan be alerted to the fact that an identified animal is in heat. Wherethe identified animal are cows, daily milk production associated eachidentified animal can be recorded. It is further possible to diagnosemastitis in an identified cow by measuring selected variables related tothe identified cow's temperature, feed consumption and milk production.It is thus evident that the system provides a means for increasingoperating efficiencies in the field of animal husbandry. Withappropriate modification, it is also possible to use the electronicidentity tag of the present invention to identify various types ofinanimate objects. It is to be understood that such modifications, ascarried out by persons skilled in the art, fall within the scope andspirit of the present invention. Indeed, it is the intention of theinventor to be limited only by the following claims.

I claim:
 1. Apparatus for producing a unique coded signal to be used ina system for feeding and monitoring animals comprising an electronicidentity means for identifying each animal, said electronic identitymeans including a power pick-up means for receiving electromagneticenergy and for providing a supply of operating power in response to theelectromagnetic energy so received, and a code generator means connectedto receive operating power from said power pick-up means for generatinga coded signal uniquely associated with each animal to be identified,and an electromagnetic field generator means for generating theelectromagnetic energy received by the pick-up means of said electronicidentity means and for selectively increasing the power content of theelectromagnetic energy so generated in order to compensate forvariations in distance between said electromagnetic field generatormeans and said electronic identity means.
 2. The apparatus set forth inclaim 1, wherein said electromagnetic field generator means includes ageneration means which outputs electromagnetic energy signals having apower content dependent upon the voltage input level supplied to saidgeneration means, said electromagnetic field generator means alsoincluding a power supply means connected to supply said generation meanswith one of a plurality of voltage input levels.
 3. The apparatus setforth in claim 2, wherein said electromagnetic field generator meansincludes a logic circuit means connected between said power supply meansand said generation means to selectively supply said generation meanswith any one of said plurality of voltage input levels.
 4. The apparatusset forth in claim 3, wherein said power supply means of saidelectromagnetic field generator means comprises a transformer having aplurality of voltage taps and a plurality of leads connecting saidplurality of voltage taps through said logic circuit means to saidgeneration means.
 5. The apparatus set forth in claim 4, wherein saidlogic circuit means of said electromagnetic field generator meansincludes a plurality of AND gates and said plurality of leads arerespectively connected from said voltage taps of said transformerthrough said plurality of AND gates to said generation means.
 6. Theapparatus of claim 5, wherein said logic circuit means of saidelectromagnetic field generator means further includes a counter meansfor successively providing enabling signals to said plurality of ANDgates.
 7. The apparatus as set forth in claim 1 wherein said codegenerator means is connected to receive operating power from said powerpick-up means for generating a binary coded signal having a value which,when decoded, uniquely represents the object to be identified.
 8. Theapparatus as set forth in claim 1 wherein said electronic identity meansfurther includes transmitting means connected to receive the codedsignal from said code generator means for transmitting the coded signalto a remote receiver, and power detection means connected between saidcode generator means, said transmitting means and said power pick-upmeans to prevent said transmitting means from transmitting the codedsignal unless the level of operating power supplied by said powerpick-up means exceeds a predetermined value.
 9. The apparatus as setforth in claim 8, wherein said power pick-up means includes a pick-upcoil into which the electromagnetic energy is coupled.
 10. The apparatusas set forth in claim 9 wherein said pick-up coil forms a transformersecondary coil and the electromagnetic field generator means includes acoil forming a transformer primary coil.
 11. The apparatus as set forthin claim 9, wherein said power pick-up means also includes a rectifiermeans connected to said pick-up coil for rectifying the electromagneticenergy coupled into said pick-up coil.
 12. The apparatus as set forth inclaim 8, wherein said power detection means includes a voltage detectorconnected to said power pick-up means and a logic means connected toreceive an enabling signal from said voltage detector only when thelevel of operating power supplied by said power pick-up means exceedssaid predetermined value.
 13. The apparatus as set forth in claim 12,wherein said logic means includes first and second inputs respectivelyconnected to receive said enabling signal from said voltage detector andthe coded signal from said code generating means, said logic means alsoincluding at least one output connected to said transmitting means suchthat the coded signal from said code generator means passes through saidlogic means to said output connected to said transmitting means onlywhen said logic means receives said enabling signal from said voltagedetector.
 14. The apparatus as set forth in claim 13, wherein said logicmeans comprises an AND gate.
 15. The apparatus as set forth in claim 14wherein said code generator means includes an RC oscillator circuitwhich provides timing pulses to initiate generation of the coded signalat a predetermined frequency.
 16. The apparatus as set forth in claim 1wherein, said code generator means includes a counter means connected tosaid power pick-up means for detecting the frequency of theelectromagnetic energy received by said power pick-up means and forproviding timing pulses which initiate the generation of the codedsignal at a frequency proportional to the frequency of theelectromagnetic energy.